Problem: $\dfrac{7}{5} - \dfrac{8}{6} = {?}$
Explanation: $ = {\dfrac{7 \times 6}{5 \times 6}} - {\dfrac{8 \times 5}{6 \times 5}} $ $ = {\dfrac{42}{30}} - {\dfrac{40}{30}} $ $ = \dfrac{{42} - {40}}{30} $ $ = \dfrac{2}{30}$